Research is underway using the method of stimulus alternation to investigate the peripheral retina. The electroretinogram and evoked potential are being taken as response measures under conditions that are uncomplicated by stray light. In addition, some work is being done in which responses are triggered by the light changes that accompany blinking and saccadic eye movement. In these experiments, the focus of stimulus patterns on the retina, their locus on the retina, and the level of the eye's adaptation is systematically varied. The responses are being examined for the separate contributions of off and on effects and for photopic and scotopic components. The methods will provide a physiological means of assessing function at several levels of the visual system.